Results of the SAVE-IT Program

1. Results of the SAVE-IT Program Matthew R Smith Gerald J Witt Debi L. Bakowski May 13, 2008

2. SAVE-IT Program Summary(SAfety VEhicles using adaptive Interface Technology) • Program start date: March 2003 • Program mission: To demonstrate a viable proof of concept that is capable of reducing distraction related crashes and enhancing safety warning effectiveness • 5 year research and development program sponsored by NHTSA, administered by Volpe • Team participants: Delphi (lead), Ford (VIRTTEX), University of Iowa & NADS, University of Michigan Transportation Research Institute (UMTRI)

3. What is the SAVE-IT system?

4. SAVE-IT Research Structure (2 years) (1.5 years) (1.5 years)

5. Crash Reduction Effectiveness vs. Acceptance Research Venue Higher On-road Acceptance 137k miles 83k miles < 200k miles Test track • 2 police-reported crashes expected every million miles Realism Acceptance evaluation requires realistic exposures Effectiveness Driving Simulator Ability to control environment facilitates the evaluation of safety effectiveness Lower Lower Higher Control

6. Adaptive Warnings

7. Support from the 100-Car Study: Distraction as the catalyst for Crashes From the 100-Car Study: Forward inattention more frequent for crashes than incidents and near misses Suggests that distraction converts incidents into crashes by undermining an avoidance maneuver that likely would have been successful. Contributing Factors (e.g., distraction, drowsiness, impairment, road conditions) Precipitating Event (e.g., lead vehicle braking event) Avoidance Response (e.g., host vehicle braking) Event Outcome Incident (Successful avoidance) Near-Miss (Late avoidance) Crash (Unsuccessful avoidance)

8. Adaptive Warnings Development • Adaptive warning goals: • reduce annoyance • improve or minimally degrade crash reduction potential. • technology must be affordable • For affordability and simplicity, only head-pose used (cognitive distraction, eye-gaze, and intent not used) Forward Collision Warning • Adaptive timing was selected for the evaluation phase • When head pose away, timing proportional to duration of away head pose • When head pose forward, only late alerts provided. • Earlier warnings were shown to improve effectiveness during distracted episodes • During attentive episodes, conflicts were usually resolved prior to a delayed warning. Lane Departure Warning • Total suppression selected for the evaluation phase • When the driver’s head pose was forward, alerts were completely suppressed • Testing revealed that alerts provided little benefit during attentive episodes Collision Percentage

9. Benefits and Acceptance of Adaptive Warnings: Test Track Results • Test track used to accelerate driver understanding of the SAVE-IT systems • Experience nuisance • Experience suppression • Experience earlier alerts • Two surprise FCW braking events (using surrogate target) provided while drivers engaged in IVIS task • Alerts were delivered earlier during the distraction episodes as designed • Earlier alerts resulted in significantly faster reaction times • Adaptive FCW rated as significantly more useful than non-adaptive • Drivers agreed significantly more with “…I would want a ___ on my next car” for adaptive than non-adaptive FCW

10. Benefits and Acceptance of Adaptive Warnings: On-road Results • A subset of the test-track drivers later drove the SAVE-IT vehicle around Michigan • Two circuits with 2 hours of adaptive/distraction mitigation, and 2 hours of nominal warning systems and no mitigation • Results revealed substantial alert suppression for both FCW and LDW • LDW alerts were reduced by 88 percent • FCW alerts were reduced by 60 percent and proportionally more false alerts (80%) and lane-change alerts (77%) were reduced than same lane alerts (65%). • The earlier timing during non-forward episodes also added extra alerts.

11. Distraction Mitigation

12. Demand-Based IVIS Distraction Mitigationand call screening Park Medium High Low Driving Demand (from Radar, Yaw, Path, Wipers, etc.) Many IVIS Features are available and many are advised against Few IVIS features are available and almost all are advised against All IVIS Features Are Available Almost all IVIS Features are available and few are advised against IVIS Function No Screen (lets all calls through) Do not disturb (let no calls through) Auto Screen (screening based on demand) Driver selects “call screening” mode

13. Distraction Mitigation: Trip Report • By saving feedback to end of the drive, avoided providing additional distraction • Acceptance data on trip report was positive and response times to lead vehicle braking were significantly reduced

14. SAVE-IT Conclusions • Adaptive warnings help alleviate the tradeoff between providing sufficient warning during distracted episodes and annoying drivers when they do not need the warnings • The challenge of adaptive systems is to function differently across driver states while preserving the perception of consistent system behavior • Providing earlier alerts during distracted episodes appears to best match the driver’s expectations for FCW systems and can help negate the effect of distraction • Trip report demonstrated high acceptance and significantly reduced response times on subsequent trials • There were many positive results, however, more work would be beneficial • The lessons learned during evaluation could be applied to improve the system further • In many cases, statistical power was insufficient or exposures insufficient for detecting statistically significant results. • Ford VIRTTEX results are still being analyzed…

15. For more information • Many SAVE-IT documents are available at: • More information on NHTSA activities and papers in this area are available at: http://www.volpe.dot.gov/hf/roadway/saveit/index.html http://www.nhtsa.gov/portal/site/nhtsa/menuitem.8f0a414414e99092b477cb30343c44cc/